System and Method for Human Body Communication Using Limited Passband

1. A transmitter using a limited passband for a human body communication system, comprising: a transmission frame generating means for human body communication which generates a transmission frame for human body communication based on data information including user identification (ID) and data scrambled into an orthogonal code generated by the user ID; a symbol mapping means for symbolizing the generated transmission frame for human body communication according to a predetermined modulating method; a spreading means for spreading the symbol outputted in the symbol mapping means; a waveform generating means for generating a baseband signal whose band is limited to a predetermined range with respect to the data spread in the spreading means; and a middle band transmitting means for modulating the baseband signal into a predetermined limited passband signal within a predetermined range while maintaining a waveguide characteristic, and wherein the modulate and limited passband signal is transmitted within the predetermined frequency range except the predetermined frequency range having a highest affect of interference from other electronic devices.

2. The transmitter of claim 1 , wherein the transmission frame generating means for human body communication includes: a preamble generator for generating a preamble for timing synchronization; a header generator for receiving data information including a transmission speed, a modulating method, user ID, and a data length transmitted from a Medium Access Control (MAC) processing unit, performing Cyclic Redundancy Check (CRC) and generating a header of the transmission frame; a data generator for receiving the data transmitted from the MAC processing unit and outputting the data at a predetermined time; a scrambler for performing data scrambling based on the orthogonal code generated by the user ID of the data information; and a frame former for generating the transmission frame for human body communication based on the generated header, the scrambled data, and the generated preamble.

3. The transmitter of claim 2 , further comprising: a channel encoding means for performing channel encoding on the scrambled data before generating the transmission frame for human body communication in the frame former.

4. The transmitter of claim 3 , further comprising: an interleaving means for interleaving channel encoded data in the channel encoding means.

5. The transmitter of claim 2 , wherein the header generator includes a data transmission rate, a modulating method, user ID, a data length, and a CRC value of the data transmission rate, the modulating method, the user ID, and the data length.

6. The transmitter of claim 1 , wherein the spreading means spreads a symbol outputted in the symbol mapping means in a time domain or a frequency domain.

7. The transmitter of claim 1 , wherein the middle band transmitting means modulates the baseband signal into a signal within the predetermined range of 5 MHz to 40 MHz.

8. A receiver in a human body communication system, comprising: a reception processing means for demodulating a limited passband signal received through a human body channel into a baseband signal; a de-spreading means for recovering symbol data by de-spreading the demodulated reception baseband signal; a symbol de-mapping means for de-mapping symbol data recovered in the de-spreading means into a data bit; and a transmission frame processing means for human body communication which divides the transmission frame for human body communication outputted in the symbol de-mapping means into a preamble, a header, and data, extracts user identification (ID) from the header, and de-scrambles the divided data into the orthogonal code generated by the user ID, wherein the reception processing means includes: a middle band receiver for demodulating a middle band reception signal received through the human body channel and converting the middle band reception signal into a baseband signal; and a reception digital front end (DFE) for performing reception gain control, DC offset control, and frequency offset control through a reception signal of the baseband outputted in the middle band receiver.

9. The receiver of claim 8 , wherein the transmission frame processing means for the human body communication includes: a frame processor for dividing the transmission frame for human body communication outputted in the symbol de-mapping means into a preamble, a header, and data; a header processor for performing Cyclic Redundancy Check (CRC) decoding on data information included in the divided header and transmitting the data information to a Medium Access Control (MAC) processing unit; a de-scrambler for de-scrambling the data divided in the frame processor into the orthogonal code generated by the user ID among the data information; and a data processor for transmitting the de-scrambled data to the MAC processing unit.

10. The receiver of claim 9 , further comprising: a de-interleaving means for de-interleaving the data divided in the frame processor.

11. The receiver of claim 10 , further comprising: a channel decoding means for performing channel decoding on the data de-interleaved in the de-interleaving means.

12. The receiver of claim 8 , further comprising: a synchronizing means for performing frame start time detection, timing synchronization, and timing offset correction by detecting a preamble from a reception signal outputted from the reception digital front end (DFE).

13. The receiver of claim 12 , further comprising: a preamble processing means for transmitting the preamble divided in the transmission frame processing means for human body communication to the synchronizing means, where the synchronizing means re-performs frame start time detection, timing synchronization, and timing offset correction based on the transmitted preamble.

14. A method for transmitting human body communication data using a limited passband which is applied to a human body communication system, comprising the steps of: providing a processor and a memory, the memory having stored thereon: a) receiving data to be transmitted to outside through a human body channel and data information including user identification (ID) from a Medium Access Control (MAC) processing unit; b) scrambling the data by using an orthogonal code generated by the user ID; c) generating a transmission frame for human body communication based on the data information and the scrambled data; d) symbolizing the generated transmission frame for human body communication according to a predetermined modulating method; e) spreading the symbol generated in the step d); and f) generating a passband signal limited within a frequency range where a human body minimizes an effect of interference while maintaining a waveguide characteristic on the data spread in the step e), and transmitting the passband signal to a human body channel, and wherein the generated and limited passband signal is transmitted in the frequency range except the frequency range having a highest affect of interference from other electronic devices.

15. The method of claim 14 , further comprising the step of: g) performing channel encoding and interleaving on the data information and the scrambled data before generating a transmission frame for human body communication in the step c).

16. The method of claim 14 , wherein in the step f), a passband signal limited to a range of 5 MHz to 40 MHz with respect to the data spread in the step e) is generated.

17. A method for receiving human body communication data using a limited passband which is applied to a human body communication system, comprising: providing a processor and a memory, the memory having stored thereon: a) demodulating a limited passband signal received through a human body channel into a baseband signal, wherein the received and limited passband signal is received from a first device transmitting the limited passband signal within a predetermined frequency range except the predetermined frequency range having a highest affect of interference from other electronic devices and wherein the received signal is transmitted within the predetermined frequency range from the first device while the first devices maintains a waveguide characteristic; b) de-spreading the demodulated reception baseband signal and recovering symbol data; c) de-mapping the symbol data recovered in the step b) into data bits; d) dividing the transmission frame for human body communication recovered in the step c) into data information and data, and extracting user identification (ID) from the divided data information; and e) generating an orthogonal code by the extracted user ID and de-scrambling and recovering the divided data into the orthogonal code.

18. The method of claim 17 , further comprising: f) transmitting the divided data information and the de-scrambled data to a Medium Access Control (MAC) processing unit.

19. The method of claim 17 , further comprising: g) performing de-interleaving and channel decoding on the data acquired in the step d).